Aug. 14 (Bloomberg) -- Boeing Co.’s 787 Dreamliner suffered
a fresh setback after ANA Holdings Inc., the model’s biggest
operator, said it discovered wiring defects in the fire-suppression system on three aircraft.

The fault, first detected on a 787 due to depart Tokyo’s
Haneda airport today, would trigger the wrong extinguisher in
the event of a blaze in one of the two engines, ANA said. Japan
Airlines Co. recalled a 787 flying to Helsinki from Tokyo as a
precaution, and Boeing said it was investigating the flaw.

“These things happen with a new aircraft,” said Robert
Stallard, an analyst at RBC Capital in London with an
“outperform” rating on Chicago-based Boeing. “When the
airlines ground the plane or regulators start becoming involved,
then it becomes something to watch out for.”

Boeing’s flagship jet, which made its commercial debut in
2011, is already under scrutiny following a fire in London last
month that U.K. investigators linked to an emergency beacon. The
787 returned to service with ANA and Japan Airlines on June 1
after a global grounding spurred by a pair of meltdowns in the
lithium-ion batteries on the carriers’ jets.

Boeing fell 2 percent to $104.16 at the close in New York
as broader U.S. stock indexes declined. That pared the shares’
gain to 38 percent this year.

Wiring Issue

ANA’s parts were replaced in two of the jets in which the
Tokyo-based carrier found the defect, which must have occurred
during the manufacturing process, said Megumi Tezuka, a
spokeswoman. The third aircraft will also be fixed by the end of
the day, she said.

Japan Air brought back the 787 from Helsinki to Narita
airport in Tokyo as a precautionary measure after being informed
of the new wiring issue by the National Transport Ministry,
company spokesman Seiji Takaramoto said.

The airline subsequently inspected all 10 of its 787s and
found no issues, he said. Among other carriers flying
Dreamliners, LOT Polish Airlines SA said its jets are flying as
scheduled, while Qatar Airways Ltd. said it has had no problems
and Norwegian Air Shuttle ASA said it was unaware of the issue.

United Continental Holdings Inc., the only U.S. Dreamliner
operator, was inspecting its 787 fleet following “preliminary
instructions from Boeing,” said Christen David, a spokeswoman.

The Chicago-based carrier plans “to complete inspections
as quickly as possible with minimal impact to our operations,”
David said in an e-mail.

Beacon Incident

U.S. regulators ordered Dreamliner operators to check
emergency radio transmitters for wire damage after a beacon was
linked to the July 12 fire in London. The Federal Aviation
Administration is working with Boeing to develop instructions
for the inspections, the agency said at the time.

Boeing delivered 73 Dreamliners to 13 customers through
Aug. 7, the company said on its website, with more than 29,000
flights flown.

Dreamliner operators resumed services after a three-month
grounding over the battery fires when authorities approved a
redesign including more protection around individual cells to
contain overheating. Ethiopian Airlines Enterprise was first to
restart flights in April, with the Japanese carriers opting for
a four-month halt as they took out ads saying the 787 was safe.